A service description format extension extends how a service description is generated for an XML Web service created using ASP.NET. Specifically, a service description format extension adds XML elements to the service description. This is useful when a SOAP extension is built to run on both the client and server side of an XML Web service, as information about SOAP extensions is not placed in the service description. If you want to add information about the SOAP extension to the service description, a client can interpret that it must run the specific SOAP extension. An example of a SOAP extension that must run on both the client and server is an encryption SOAP extension. If an encryption SOAP extension runs only on the server and it encrypts return values before sending them back to the client, the client must have the SOAP extension running to decrypt the SOAP message. Otherwise, the client cannot process the return value.

Use the following steps to build a service description format extension: